ML18353A987

Letter Final Response to IE Bulletin 75-05

ML18353A987
Person / Time
Site:	Palisades  (DPR-020)
Issue date:	07/25/1975
From:	Sewell R Consumers Power Co
To:	James Keppler NRC/IE, NRC/RGN-III
References
IEB-75-005
Download: ML18353A987 (5)

Text

General Offices: 212 West Michigan Avenue;.Jackson, Michigan 49201

• Area Code 517 788-0550 July.25, 1975 Mr. James G. Keppler US Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, IL 60l37 DOCKET.50-255, LICENSE DPR~20..

PALISADES PLANT, IE BULLETIN 75-~05..

This letter is written.toprovide a final response to. IE Bulletin 75-05.

Previous responses were submitted: May l6 and June 17-, 1975.

The informa-tion requested* in the* "Bulietin ti is repeated to. facilitate. our response.

-Iriformat-ion Requested

a.

"The* :design requirements which the various suppressors are intended to meet*,_ such as velocity, acceleration, load, etc, also indicate the margin available* between the* design requirements. and the requirements. specified for purchase of these components.n Response:* Be_rgen* Patterson Snubbers There a.re.f'ourteen:Bergen Patterson Snilbbers installed at Palisades.

Twelve ot the* snubbers are located.* on the inain steam lines and two a.re located on the feed-water pipi.p.g between-Feed~Water Heater E-6A & B.

HSSA~20*

HSSA~50

. Model.. No HSSA-lO JUL'

• *Main SteaJli. Line *sn.ubbers

• *Quantity 8

4 Manufacturer's.

• Load*

20,°000. Lb 50*, o"oo. Lb

• Feea~wa.ter*snubbers Quantity. -

2 Manufacturer's. *

• • • Load 10,000. Lb Palisades Design Requirements 20,000.Lb 40,000. Lb Palisades Des_ign

• *Requirements Unknown

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For the-unknown ~eed-water snubbers it is assumed that the size selection made during the plant design phase is adequate for the imposed loading conditions.

For normal operation, the Bergen Patterson equipment acts as a conventional hydraulic snubber strut which_ permits the f'ree thermal growth of the piping, but acts as a rigid restraint against any. shock or vibration force that gen-erates a piston rod velocity in excess of ten inches per minute.

The closure

_ is designed to be effected within 1/32 inch of a piston rod movement.

The Palisades snubbers have a six-inch stroke and the snubbers cold setting are set at around three inches which insures the snubbers design operation in

• either snubber movement direction *

. Response:

Grinnell Snubbers -

There are 16 Grinnell Snubbers installed.at Palisades. All 16 snubbers are located on the steam generators, eight-pe~- generator.

The 16 Palisades Grinnell Snubbers have eight;._inch bores and five-inch strokes and were ordered to an e_ngineering specification, Spec No 70P:-21.

The pertinent des_ign data des_ignated in the specification were that:

The _

snubbers on the* same side of th_e* ste~ ggnerator are assumed to take equal loads; loading, impulse* loading 0.2 x 10.lb at velocity up to 2.8 fps -

static load of 0.443.x l06_wheh acting as a stop, warm-up essentially a*lb at velocity of approximately 0~2 in/h. It was also specified that the hydraulic cylinders be* double acting and have a rated stroke length of five inches..

These* sway arresters have a maximum stroke velocity of: approximately one inch per minute and were physically load tested to insure all des_ign specifications were in.et..

IIiformatidn *Reg_i.tested

b.

"Describe the* testing of the* hydraulic suppressors-conducted by you or your supplier(s)*prior to.installation to assure their operation in accordance With des_ign specifications * "

Response

Bergen Patterson SnUb'bers The followi_ng is taken from Be_rgen Patterson's. explanation of: their testi_ng criterion:

"Each* individual unit is tested to.. demonstrate. :fluid containment in-tegrity and operational characterisitics.

• It is necessary to describe both the design criteria and testing procedure with relation to a time frame in_. that both. the* manufacturing technique and testi_ng apparatus

_and procedure were changed when-. the manifold configuration model re-placed the* external pipe.configuration model:

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OPERATIONAL DESIGN CRITERIA (Applies to All Bore Sizes)

1. Piston.shall be free to move in either direction with poppet valves re-

.maining :fully open for all piston velocities 10 inches per minute and slower.

• Tolerance plus or minus* 2 inches per minute*.

(Applies to all

• models.)

2.

Poppet valves shall be des.igned for closure when piston_ velocity reaches 10 inches per minute for both compression and extension *stroke.

Tolerance on velocity for closure shall be plus or minus 2 inches per minute*.

(Applies to all models.)

3. Orifice shall permit continued piston movement in either direction after valve closure at a rate. of 4 to. 6 i~ches per minute at rated design cap-acity*.

Applies to all models except units made prior to June 1969.

These can be identi-fied' as being units. with. external pipi.ng -

to the' accumulator with.the following_

serial numbers:

• 487278 throu 487820*~

For these specific units, the.bypass rate.

is approximately:.

15

• inches per minute for 2-1/2"- Bore Uni ts_

10 inches.per minute for 3-l/2n_& 4" Bore Units" The* followi.ng testi_ng procedure as ezjilained by Be.rgen Patterson applies to the Palisades* snubbers: *

"Former testi.n~ procedure (applicable to all units tested prior to.October* 1972 ~Serial numbers~

All six digit numbers without prefix letter and :F6o635 thril F81-30*2 __

• "Tolerance on. rates* are established* as 8: goal to maintain uniformity of"_ pro-duction.

Acceptance range is established by periodic review of individual test resUlts: on. all units. in a production run and the* range is mutually es-tablished* and reduced as production' COntrol techniques are improved. II

• • The* f'eed:....water* snubbers were inade prior to June 1969 and have serial. numbers 487451 and 487467. 'The' main steain line snubbers all were manufacturered after June 1969.-

"The* operatiEinal characterisitcs of the assembled unit is established

• by determining the contr.ol valve* fluid flow characteristics at the various phases of operation.

This is done by setting up each individ-ual control valve in a fluid test stand and physically capturing and measuri_ng the fluid flow vo_lume over a specific time period and com-paring the results to establish ininimum,.-ma.x.imum flow rates at* the test pressure that are equivalent to flow rates at actual design rated pressure.

These values* were or_iginaily determined by caJ.cula:tions and then by physical experiment using valves from units whose fully assem-*

bled characteristics had been established as being within the piston velocity tolerance ~anges* for.the.various phases of operation such as valve closure and bypass rates *. The cylinder is filled :with fluid prior to mounting of valve usi,ng a piston stroki_ng operation and tne valve is then*.mounted* and filled usi_ng a poliri,ng operation.

The fluid con-tainment integrity of the cylinders with valve body attached is estab-lished by* applyi_ng 3500 psi fluid pressure thru the valve port to which

. the acclimul.ator is normally attached and visually checking for leaks over a specific time period.

The accumulator* is then. attached and cha:rged.with.fluid, the unit is cleaned and allowed to stand for a period of time and then checked visually for leakage.

nrn addition to -the* above described testing proced'ures performed on each individual unit,. dynamic testi_ng has been performed on some selected units to demonstrate* operational characteristics during shock loading

• and vibration conditions."

Response:*. Grinnell* Snubbers The.Palisades.Grinnell hydraulic shoCk and sway arresters have passed the fol-lowing inspections and tests:*

1.. Snubber Valves.;.. Low Lak.e_age Type A. Allparts.were thoroughly inspected.and cleaned, deburred, when necessary, and free.of all* chips.*

B.

The* assembled.valves* are pressure tested and assigned serial numbers.

This test determines that leakage past the snubber piston at 5500 psi is not_ greater.than a specified leak~ge.

C *. The valves* are then delivered for assembly in special requirement

• Fig 200. suppressors.

2.~ ShoCk: Suppressor Assembly A. The S:uppressors.are assembled, tension and compression load capacity tested* wi. th. a Biehle* load capacity. testi_ng machine.*

B.. The* assembly is filled and. tested for air pockets.* The air is bled off, if present.. This bleeding sequence insures that the* snubbers are full" and ready for service.*

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The assembly is then tested for proper operation by noticing the piston rod motion during the test.

Under the test conditions if the rod motion exceeds 1

11 per minute, the valve assembly on the snubber is replaced.

Information Requested

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Describe the surveillance (including testi_ng) programs now under way or planned by you to assure continued operability of the hydraulic suppressors under the* des_ign *conditions throughout the* life of the* facility."*

Response

Be.rgen Patterson Snubbers.

Presently, the'.Palisades Snubbers are covered by a Preventive Maintenance Procedure under which. the snubber fluid levels are checked and the snubbers are inspected fox leaks every 30 days.* '

Response

Grinnell Snubbers The* Grinnell Snubbers have a common fluid system and the reservoir level is

.cheeked* prior to: each start-up, as well* as the snubber system bei.ng inspected for overall* integrity.

• Response:* Testing P:r:ograms The* testi_ng pr_ograms required* to assure continued operability. of the hydraulic suppressors under. the* des_ign conditions. thrcmghoiJ.t the life of the :facility will* be* stated.in compliance With the required Technical Specifications change requested* in Robert A. Purple's;*USNRC, June 30,.1975 letter to R. B. Sewell.

CC:*. File*